Tissue resection apparatus

ABSTRACT

A tissue resection apparatus is provided which includes an outer tube with a helical coil disposed on a distal end. The coil is provided with a first electrode. A central tube has a distal edge profile comprising one or more surface segments. One of the surface segments includes a second electrode. The central tube is slidably disposed within the outer tube and positioned such that second electrode opposes at least a portion of the first electrode. A cutting tube is slidably disposed within the central tube and includes a cutting edge.

CROSS-REFERENCES TO OTHER RELATED PATENT APPLICATIONS

This application claims priority from application Ser. No. 62/712,545filed Jul. 31, 2018, which is incorporated herein by reference in itsentirety.

This application claims priority from application Ser. No. 62/728,170filed Sep. 7, 2018, which is incorporated herein by reference in itsentirety.

This application claims priority from application Ser. No. 62/744,797filed Oct. 12, 2018, which is incorporated herein by reference in itsentirety.

This application claims priority from application Ser. No. 62/749,302filed Oct. 23, 2018, which is incorporated herein by reference in itsentirety.

This application claims priority from application Ser. No. 62/756,234filed Nov. 6, 2018, which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a system, device and method for tissueresection. More particularly, the present invention relates to a system,device and method for lesion removal.

2. Discussion of the Related Art

Cancer is not a single disease, but rather a collection of relateddiseases that can start essentially anywhere in the body. Common amongstall types of cancer is that the body's cells begin to divide withoutstopping, proliferating and potentially spreading into surroundingtissues. In the normal course of events, cells grow and divide to formnew cells as required by the body and when they become damaged or old,they die, and new cells replace the damaged or old cells; however,cancer interrupts this process. With cancer, the cells become abnormal,and cells that should die do not and new cells form when they are notneeded. These new cells can reproduce or proliferate without stoppingand may form growths called tumors.

Cancerous tumors are malignant, which means they can spread into orinvade surrounding healthy tissue. In addition, cancer cells can breakoff and travel to remote areas in the body through blood or in the lymphsystem. Benign tumors, unlike malignant tumors, do not spread or invadesurrounding tissue; however, they may grow large and cause damage. Bothmalignant and benign tumors may be removed or treated. Malignant tumorstend to grow back whereas benign tumors can grow back but are much lesslikely to do so.

Cancer is a genetic disease in that it is caused by changes in the genesthat control the ways that cells function, especially in how they growand divide. Genetic changes that cause cancer may be inherited or theymay arise over an individual's lifetime as a result of errors that occuras cells divide or because of damage to DNA caused by certainenvironmental exposure, for example, industrial/commercial chemicals andultraviolet light. The genetic changes that may cause cancer tend toaffect three types of genes; namely proto-oncogenes which are involvedin normal cell growth and division, tumor suppressor genes which arealso involved in controlling cell growth and division, and DNA repairgenes which, as the name implies, are involved in repairing damaged DNA.

More than one-hundred distinct types of cancer have been identified. Thetype of cancer may be named for the organ or tissue where the cancersarise, for example, lung cancer, or the type of cell that formed them,for example squamous cell cancer. Cancer, unfortunately, is a leadingcause of death both in the United States and world-wide. According tothe World Health Organization, the number of new cancer cases will riseto twenty-five (25) million per year over the next two decades.

Lung cancer is one of the most common cancers today. According to theWorld Cancer Report 2014 from the World Health Organization, lung canceroccurred in 14 million people and resulted in 8.8 million deathsworld-wide, making it the most common cause of cancer-related death inmen and the second most common cause of cancer-related death in women.Lung cancer or lung carcinoma is a malignant lung tumor that if leftuntreated can metastasize into neighboring tissues and organs. Themajority of lung cancer is caused by long-term tobacco smoking; however,about 10 to 15 percent of lung cancer cases are not tobacco related.These non-tobacco cases are most often caused by a combination ofgenetic factors and exposure to certain environmental conditions,including radon gas, asbestos, second-hand tobacco smoke, other forms ofair pollution, and other agents. The chance of surviving lung cancer aswell as other forms of cancer depends on early detection and treatment.

When a lesion is detected in the lungs, a biopsy is performed and sentfor study. If it is determined that the lesion is cancerous, a secondprocedure may be performed to remove the cancer. If the biopsy revealsno cancer, it may be correct, or the biopsy did not pick the cancerouscells. Accordingly, there exists a need for removing the whole lesion inone single procedure so that an accurate diagnosis may be performed.

SUMMARY OF THE INVENTION

The system, device and method for performing lung lesion removal of thepresent invention overcomes the limitations associated with the priorart.

The present invention relates to a system, device and method forperforming lung lesion removal. A lung needle biopsy is typicallyperformed when an abnormality is found on an imaging test, for example,an X-ray or CAT scan. In a lung needle biopsy, a fine needle is used toremove sample of lung tissue for examining under a microscope todetermine the presence of abnormal cells. Tissue diagnosis ischallenging in small (<6 mm) and intermediate (6-12 mm) nodules. CTguided biopsy of peripheral lesions, either through the chest wall (80%)or by means of a bronchoscope (20%) yields only a 0.001-0.002 cm2 ofdiagnostic tissue, and as such, cancer, when present, is onlysuccessfully identified in 60% of small and intermediate nodules.Although bronchoscopic techniques and technology continue to evolve,biopsy accuracy, specificity, and sensitivity will always be limitedwhen dealing with small and intermediate nodules in the periphery of thelung.

If it is determined that the lesion is cancerous, a second procedure maybe performed to remove the lesion and then followed up with chemotherapyand/or radiation. The second procedure most likely involves lungsurgery. These procedures are typically done through an incision betweenthe ribs. There are a number of possible procedures depending on thestate of the cancer. Video-assisted thoracic surgery is a less invasiveprocedure for certain types of lung cancer. It is performed throughsmall incisions utilizing an endoscopic approach and is typicallyutilized for performing wedge resections of smaller lesions close to thesurface of a lung. In a wedge resection, a portion of the lobe isremoved. In a sleeve resection, a portion of a large airway is removedthereby preserving more lung function.

Nodules deeper than 2-3 cm from the lung surface, once identified assuspicious for cancer, are difficult to localize and excise usinglaparoscopic or robotic lung sparing technique despite pre-procedureimage guided biopsy and localization. Thus, surgeons perform an openthoracotomy or lobectomy to remove lung nodules that are 2-3 cm from thelung surface. A thoracotomy is an open approach surgery in which aportion of a lobe, a full lobe or an entire lung is removed. In apneumonectomy, an entire lung is removed. This type of surgery isobviously the most aggressive. In a lobectomy, an entire section or lobeof a lung is removed and represents a less aggressive approach thanremoving the entire lung. All thoracoscopic lung surgeries requiretrained and experienced thoracic surgeons and the favorability ofsurgical outcomes track with operative experience.

Any of these types of lung surgery is a major operation with possiblecomplications which depend on the extent of the surgery as well as thepatient's overall health. In addition to the reduction in lung functionassociated with any of these procedures, the recovery may take fromweeks to months. With a thoracotomy, spreading of the ribs is required,thereby increasing postoperative pain. Although video-assisted thoracicsurgery is less invasive, there can still be a substantial recoveryperiod. In addition, once the surgery is complete, full treatment mayrequire a system chemotherapy and/or radiation treatment.

As set forth above, a fine needle biopsy may not prove to be totallydiagnostic. The fine needle biopsy procedure involves guiding a needlein three-dimensional space under two-dimensional imaging. Accordingly,the doctor may miss the lesion, or even if he or she hits the correcttarget, the section of the lesion that is removed through the needle maynot contain the cancerous cells or the cells necessary to assess theaggressiveness of the tumor. A needle biopsy removes enough tissue tocreate a smear on a slide. The device of the present invention isdesigned to remove the entire lesion, or a substantial portion of it,while minimizing the amount of healthy lung tissue removal. This offersa number of advantages. Firstly, the entire lesion may be examined for amore accurate diagnosis without confounding sampling error, loss of cellpacking or gross architecture. Secondly, since the entire lesion isremoved, a secondary procedure as described above may not be required.Thirdly, localized chemotherapy and/or energy-based tumor extirpation,such as radiation, may be introduced via the cavity created by thelesion removal.

In at least one embodiment, the invention encompasses a tissue resectionmechanism comprising an outer tube having a helical coil disposed on adistal end where the coil includes a first electrode. A central tube isprovided having a distal edge profile including one or more surfacesegments, at least one of surface segments includes a second electrode.The central tube is slidably disposed within the outer tube and isposition such that the second electrode opposes at least a portion thefirst electrode. A cutting tube includes a cutting edge slidablydisposed within the central tube and the cutting tube is configured toadvance at least as far as one of the coil segments.

In another embodiment the invention encompasses a tissue resectionmechanism comprising an outer tube having a helical coil disposed on adistal end where the coil includes a first electrode. A central tube isprovided having a distal edge profile including one or more surfacesegments, at least one of surface segments includes a second electrode.The central tube is slidably disposed within the outer tube and isposition such that the second electrode opposes at least a portion thefirst electrode. First and second ligating electrodes are disposed inthe central tube and exposed to a central tube lumen. A snare isdisposed in the central tube between the first and second ligatingelectrodes. A cutting tube includes a cutting edge slidably disposedwithin the central tube and the cutting tube is configured to advance atleast as far as one of the coil segments.

In still another embodiment the invention encompasses a tissue resectionmechanism comprising an outer tube having a helical coil disposed on adistal end where the coil includes a first electrode. A central tube isprovided having a distal edge profile including one or more surfacesegments, at least one of surface segments includes a second electrode.The central tube is slidably disposed within the outer tube and isposition such that the second electrode opposes at least a portion thefirst electrode. First and second ligating electrodes are disposed inthe central tube and exposed to a central tube lumen. An amputationsnare is disposed in the central tube and a ligation snare is disposedin the central tube. A cutting tube includes a cutting edge slidablydisposed within the central tube and the cutting tube is configured toadvance at least as far as one of the coil segments.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following, more particular description of preferredembodiments of the invention, as illustrated in the accompanyingdrawings.

FIG. 1 depicts a tissue resection device in accordance with anembodiment of the invention.

FIG. 2 illustrates a sectional view of the tissue resection device ofFIG. 1.

FIG. 3 shows a sectional view of a tissue resection device in accordancewith an embodiment of the invention.

FIG. 4 depicts a sectional view of a tissue resection device inaccordance with an embodiment of the invention.

FIG. 5 illustrates an exemplary anchor that may be employed in a lesionremoval method in accordance with an embodiment of the invention.

FIG. 6 shows a series of incision blades for use in a lesion removalmethod in accordance with an embodiment of the invention.

FIG. 7 displays tissue dilators suitable for use in a lesion removalmethod in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The resection device of the present invention comprises an energy-basedarrangement capable of penetrating tissue towards a target lesion. Inone embodiment depicted in FIG. 1, tissue resection device 1100 includesan outer tube 1105 is provided having a distal edge profile and havingan inner diameter ID_(outer). A coil 1110 is attached to outer tube 1105where the coil turns are spaced from and opposed to a distal end ofouter tube 1105. Coil 1110 preferably has a slightly blunted tip 1115 tominimize the possibility that it will penetrate through a blood vesselwhile being sufficiently sharp to penetrate tissue such as pleura andparenchyma. In some embodiments, coil 1110 may take the form of a helixhaving a constant or variable pitch. Coil 1110 may also have a variablecross-sectional geometry. An electrode 1130 is disposed on a surface orembedded within coil 1110.

In some embodiments, as illustrated in FIG. 1, coil 1110 may include aplurality of contiguous coil segments, e.g., coil segments 1120 and1125. Coil segment 1120 comprises a helical member having a pitch ofzero, e.g., a generally planar open ring structure, having an innerdiameter ID_(coil) and an outer diameter OD_(coil). Coil segment 1125comprises a helical structure of constant or variable pitch and constantor variable cross-sectional geometry. In this embodiment, electrode 1130may be disposed on a surface of or embedded in coil segment 1120.

A central tube 1200 is provided having a distal end with an edge profilecomprising one or more surface segments and having an outer diameterOD_(central) and an inner diameter ID_(central). As illustrated in FIG.2, an electrode 1205 is disposed on or embedded within at least one ofthe surface segments. Central tube 1200 is slidably disposed withinouter tube 1105 and positioned such that electrode 1205 opposes andoverlaps at least a portion of electrode 1130. The space betweenelectrode 1205 and electrode 1130 is referred to as the tissue clampingzone. In keeping with an aspect of the invention, OD_(central)>ID_(coil)and OD_(coil)>ID_(central). In some embodiments, OD_(central) is aboutequal to OD_(coil). Accordingly, Central tube 1200 may be advancedthrough the tissue clamping zone towards coil 1110 such that electrode1205 abuts electrode 1130.

A cutting tube 1300 is slidably disposed within central tube 1200. Thedistal end of cutting tube 1300 is provided with a knife edge tofacilitate tissue cutting.

To enable tissue resection, the resection device 1100 may be insertedinto tissue and outer tube 1105 may be advanced a predetermined distancetowards a target. Coil segment 1125 allows the device to penetrate thetissue in a manner similar to a cork screw. As coil segment 1125penetrates tissue, any vessel in its path is either moved to planar coilsegment 1120 or pushed away from the coil 1100 for subsequent turns.Coil tip 1115 is made blunt enough to minimize chances that it willpenetrate through a blood vessel while still sharp enough to penetratecertain tissue such as the lung pleura and parenchyma. Central tube 1200may then be advanced a predetermined distance towards the target. Anyvessels that are disposed in the tissue clamping zone will be clampedbetween electrode 1130 and electrode 1205. The vessels can then besealed by the application of bipolar energy to electrode 1130 andelectrode 1205. Once blood vessels are sealed, cutting tube 1300 isadvanced to core the tissue to the depth that outer tube 1105 hasreached. The sealing and cutting process can be repeated to create acore of desired size.

In keeping with an aspect of the invention, the resection device may befurther configured to dissect a target lesion and seal tissue proximatethe dissection point. To facilitate dissection and sealing, asillustrated in FIG. 3, central tube 1200 is provided with a ligationsnare 1230, first and second ligation electrodes 1215 and 1220, anamputation snare 1225 and a ligation snare 1230. As used herein, theword “snare” refers to a flexible line, e.g., a string or a wire. Theinner wall surface of central tube 1200 includes upper and lowercircumferential grooved pathways 1212 and 1214 disposed proximate thedistal end. The first and second ligation electrodes 1215 and 1220 aredisposed on the inner wall of central tube 1200 such that lowercircumferential groove 1214 is between them. Upper grooved pathway 1212is disposed axially above ligation electrodes 1215 and 1220.

Ligation snare 1230 is disposed in lower circumferential groove 1214 andextends through central tube 1200 and axially along the outer wallsurface to a snare activation mechanism (not shown). Amputation snare1225 is disposed in upper circumferential groove 1212 and extendsthrough central tube 1200 and axially along the outer wall surface to asnare activation mechanism (not shown). The outer surface of centraltube 1200 may be provided with a plurality of axially extending groovedpathways which receive amputation snare 1225, ligation snare 1230 andare in communication with upper and lower circumferential groovedpathways 1212 and 1214. In addition, electrode leads for ligationelectrodes 1215 and 1220 may extend to an energy source via the axiallyextending grooved pathways.

In operation, the resection device of this embodiment can detach andseal the tissue core. Cutting tube 1300 may be retracted to exposeligation snare 1230 which is preferably made of flexible line, e.g.,suture. Ligation snare 1230 may be engaged to snag tissue and pulltissue against the inner wall surface between first and second ligationelectrodes 1215 and 1220. Bipolar energy is then applied to first andsecond electrodes 1215 and 1220 to seal, i.e., cauterize, the tissue.Once sealed, cutting tube 1300 may be further retracted to exposeamputation snare 1225 which may then be activated to sever the tissuecore upstream from the point where the tissue was sealed (ligationpoint). In some embodiments, amputation snare 1225 has a smallerdiameter than that of ligation snare 1230. The smaller diameterfacilitates tissue slicing. Accordingly, the resection device 1100according to this embodiment both creates a tissue core and disengagesthe core from surrounding tissue.

In an alternative embodiment, the resection device of the invention isprovided with a single snare disposed between ligation electrodes whichboth ligates and cuts tissue. In this embodiment, the single snare firstpulls tissue against the inner wall surface of central tube 1200 betweenligation electrodes 1215 and 1220. Bipolar energy is then applied tofirst and second electrodes 1215 and 1220 to seal, i.e., cauterize, thetissue. Once sealed, the snare is further pulled to sever the tissuecore.

In yet another embodiment, cutting and sealing may be performed withoutemploying electrodes. In this embodiment, ligation snare 1230 includes aset of knots 1235 and 1240 which tighten under load, shown, for example,in FIG. 4. Ligation is performed by retracting cutting tube 1300 toexpose ligation snare 1210 and activating ligation snare 1230 whichlassos tissue as ligation knot tightens. Once the tissue is lassoed,cutting tube 1300 may be further retracted to expose amputation snare1225 which may then be activated to sever the tissue core upstream fromthe point where the point where the tissue was lassoed.

The present invention also contemplates a method and system for usingthe resection device to remove tissue lesions, for example, lunglesions. The method generally comprises anchoring the lesion targetedfor removal, creating a channel in the tissue leading to the targetlesion, creating a tissue core which includes the anchored lesion,ligating the tissue core and sealing the surrounding tissue, andremoving the tissue core including the target lesion from the channel.

Anchoring may be performed by, any suitable structure for securing thedevice to the lung. Once the lesion is anchored, a channel may becreated to facilitate insertion of resection device 1100. The channelmay be created by making an incision in the lung area and inserting atissue dilator and port into the incision. A tissue core which includesthe anchored lesion may be created. In keeping with the invention,resection device 1100 may be inserted into the channel and used tocreate the tissue core, to ligate the tissue core and to seal the tissuecore and sever it from the surrounding tissue as described hereinabove.The tissue core may then be removed from the channel. In keeping withthe invention, a cavity port may be inserted in the channel tofacilitate subsequent treatment of the target lesion site throughchemotherapy and/or energy-based tumor extirpation such as radiation.

The anchor depicted in FIG. 5 is suitable for use in performing themethod for removing tissue lesions described herein. The anchorcomprises an outer tube 1422 having a sufficiently sharp edge to piercethe chest cavity tissue and lung without causing excess damage and aninner tube 1424 disposed within outer tube 1422. One or more tines orfingers 1426 formed from shape memory material, e.g., Nitinol, preformedare attached to the end of inner tube 1424. Outer tube 1422 isretractably disposed over inner tube 1424 such that when outer tube 1422is retracted, tines 1426 assume their preform shape as shown. In keepingwith the invention, outer tube 1422 is retracted after it has piercedthe lung lesion thereby causing tines 1426 to engage the lung lesion.Other suitable anchors may include coils and suction-based structures.

The incision blades depicted in FIG. 6 are suitable for use inperforming the method for removing tissue lesions described herein. Onceanchor 1400 is set, it is preferable to create a small cut or incisionto facilitate insertion of chest wall tissue dilator. Incision blades1605 are used to make a wider cut. Successive incision blades 1605include a central aperture which allows them to be coaxially advancedalong the anchor needle 1405 to create a wider cut in the chest wall,with each successive blade being larger than the previous blade, therebyincreasing the width of the incision.

The tissue dilator depicted in FIG. 7 is suitable for use in performingthe method for removing tissue lesions described herein. The tissuedilator may comprise any suitable device for creating a channel inorganic tissue. In one exemplary embodiment, the tissue dilator assemblyincludes a single cylindrical rod with rounded end 1510 or a cylindricalrod with rounded end and a rigid sleeve arrangement 1515. Successivetissue dilators are coaxially advanced along the anchor needle to createtissue tract or channel in the chest wall, with each successive dilatorbeing larger than the previous dilator, thereby increasing the diameterof the channel. Once the final dilator with rigid sleeve is deployed,the inner rod 1505 is removed while leaving the rigid sleeve in theintercoastal space between ribs to create direct passage to the lungpleura.

Any tissue resection device capable of penetrating lung tissue andcreating a tissue core including a target lesion is suitable for use inperforming the method for removing tissue lesions described herein.Tissue resection device 1100 described hereinbefore is preferred.

Once tissue resection device 1100 is removed, a small channel in thelung exits where the target lesion was removed. This channel may beutilized to introduce an energy-based ablation device and/or localizedchemotherapy depending on the results of the tissue diagnosis.Accordingly, the method and system of the present invention may not onlybe utilized to ensure an effective biopsy is performed but also completeremoval of the lesion with minimal healthy lung tissue removal.

Although shown and described is what is believed to be the mostpractical and preferred embodiments, it is apparent that departures fromspecific designs and methods described and shown will suggest themselvesto those skilled in the art and may be used without departing from thespirit and scope of the invention. For example, the systems, devices andmethods described herein for removal of lesions from the lung. It willbe appreciated by the skilled artisan that the devices and methodsdescribed herein may are not limited to the lung and could be used fortissue resection and lesion removal in other areas of the body. Thepresent invention is not restricted to the particular constructionsdescribed and illustrated, but should be constructed to cohere with allmodifications that may fall within the scope of the appended claims.

What is claimed is:
 1. A tissue resection mechanism comprising: an outertube having a helical coil disposed on a distal end, the coil includinga first electrode; a central tube having a distal edge profile includingone or more surface segments, at least one of surface segments includinga second electrode, said central tube being slidably disposed withinsaid outer tube and being position such that the second electrodeopposes at least a portion the first electrode; a cutting tube includinga cutting edge slidably disposed within said central tube, said cuttingtube configured to advance at least as far as one of the coil segments.2. The tissue resection device of claim 1 where the coil includes firstand second contiguous coil segments, the first coil segment includingthe first electrode.
 3. The tissue resection device of claim 2 whereinthe first coil segment comprises a generally planar open ring.
 4. Thetissue resection device of claim 2 wherein the first coil segment ishelical and has a pitch of zero.
 5. The tissue resection device of claim2 wherein the second coil segment is helical and has a constant pitch.6. The tissue resection device of claim 5 wherein the second coilsegment has a variable pitch.
 7. The tissue resection device of claim 2wherein the first coil segment is helical and has a first pitch and thesecond coil segment is helical and has a second pitch, at least one ofthe first and second pitches is variable.
 8. The tissue resection deviceof claim 1 wherein the second coil segment includes the blunt tip. 9.The tissue resection device of claim 1 wherein the first and secondelectrodes have surface profiles that are substantially matching. 10.The tissue resection device of claim 2 wherein the first coil segmenthas an inner diameter and an outer diameter and said central tubeincludes an inner and outer diameter wherein the outer diameter of thecentral tube is greater than the inner diameter of the first coilsegment and the outer diameter of the first coil segment is greater thanthe inner diameter of said central tube.
 11. The tissue resection deviceof claim 2 wherein the first coil segment has an outer diameter and saidcentral tube has an outer diameter that is about equal to the outerdiameter of the first coil.
 12. A tissue resection mechanism comprising:an outer tube having a helical coil disposed on a distal end, the coilincluding a first electrode; a central tube having a distal edge profileincluding one or more surface segments, at least one of surface segmentsincluding a second electrode, said central tube being slidably disposedwithin said outer tube and being position such that the second electrodeopposes at least a portion the first electrode; first and secondligating electrodes disposed in said central tube and exposed to acentral tube lumen; a snare disposed in said central tube between saidfirst and second ligating electrodes; and a cutting tube including acutting edge slidably disposed within said central tube, said cuttingtube configured to advance at least to one of the coil segments.
 13. Thetissue resection mechanism of claim 12 wherein said central tubeincludes an inner surface with a circumferential grooved pathway andsaid snare is disposed in the circumferential grooved pathway.
 14. Thetissue resection mechanism of claim 13 wherein said central tubeincludes an outer surface having a plurality of axially extendinggrooved pathways, at least one of the axially extending grooved pathwaysbeing in communication with the circumferential grooved pathway and saidsnare axially extending from the circumferential grooved pathway alongone of the plurality of axially extending grooved pathways.
 15. A tissueresection mechanism that gathers, compresses and seals fluid vesselscomprising: an outer tube having a helical coil disposed on a distalend, the coil including a first electrode; a central tube having adistal edge profile including one or more surface segments, at least oneof surface segments including a second electrode, said central tubebeing slidably disposed within said outer tube and being position suchthat the second electrode opposes at least a portion the firstelectrode; first and second ligating electrodes disposed in the centraltube and exposed to a central tube lumen; an amputation snare disposedin said central tube; a ligation snare disposed in said central tube;and a cutting tube including a cutting edge slidably disposed withinsaid central tube, said cutting tube configured to advance at least toone of the coil segments.
 16. The tissue resection mechanism of claim 15wherein said ligation snare is disposed between said first and secondligating electrodes.
 17. The tissue resection mechanism of claim 15wherein said ligation snare is a flexible line having a first diameter.18. The tissue resection mechanism of claim 16 wherein said amputationsnare is disposed proximal to said ligating snare.
 19. The tissueresection mechanism of claim 19 wherein said amputation snare includes aflexible line having a second diameter that is smaller than the firstdiameter.
 20. The tissue resection mechanism of claim 15 wherein saidcentral tube includes an inner surface having first and second acircumferential grooved pathways, said ligation snare being disposed inthe first circumferential grooved pathway and said amputation snare isdisposed in the second circumferential grooved pathway.